JPS6340903A - Heater controller - Google Patents

Abstract

PURPOSE:To exactly derive each control coefficient even under a thermal mutual interference of each heater, by bringing simultaneously each of other heaters to an electric conduction control, based on their temperature detecting signal and control parameter, in the course of a forced variation control of each electric conduction current. CONSTITUTION:Heaters 10-1-10-4 are provided on a heating cylinder 12 of an injection molding device, a thermal interference is generated between each adjacent one of them, their temperatures are detected by sensors 14-1-14-4, respectively, and each detecting signal is inputted to a CPU 18 through an A/D converter 16. Subsequently, a set value for showing a target temperature of each heater, which has been stored in each channel area, respectively, of a RAM 20, and stored in the same area is given to the CPU 18 from a setting device 22. Also, in the same storage area, control parameters P, I and D are stored, respectively, and in the CPU 18, a control signal for making a tempera ture input value coincide with the set value is led out by a PID arithmetic operation, and an electric conduction current corresponding to said control signal is given to the heaters 10-1-10-4 through an electric conduction circuit 26.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a heater control device that simultaneously controls energizing current supplied to each of a plurality of heaters based on a temperature detection signal and a control parameter of each heater. The present invention relates to a heater control device that fluctuates and controls each energizing current and obtains each control parameter based on a temperature detection signal during that period.

(Summary of the Invention) In the present invention, the fluctuation control of the energized current performed to obtain each control parameter is sequentially performed for each energized current, and during that time, the other energized currents that are not subjected to the fluctuation control are It is directly controlled based on the detection signal and control parameters.

(Prior art and its problems) In this type of conventional equipment where each control parameter is required,
During this calculation, the current flowing to each heater is stopped at the same time, and then the current flowing to the heaters is simultaneously restarted.

During that time, the temperature detection signal of each heater changes as shown in FIG. 2, for example, and each control parameter is determined from the rate of change of the temperature signal when the energization is stopped and when it is restarted.

However, in the past, each control parameter was determined using the temperature detection signal obtained when each energizing current was fluctuatedly controlled at the same time, so these temperature detection signals had an error corresponding to the thermal interference valve of each heater. Therefore, there was a problem that each control parameter could not be determined with high accuracy.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems, and
The purpose is to provide this type of heater control device that allows each control parameter to be determined accurately despite thermal interference between each heater.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention provides an energization method that simultaneously controls the energization current supplied to each of a plurality of heaters where thermal interference occurs based on the temperature detection signal and control parameter of each heater. a control means, an energization amount variation control means for forcibly controlling the variation of each energization current, a variation control current specifying means for sequentially specifying the energization current to be fluctuated, and a control parameter for each energization current for controlling the energization current. It is characterized by comprising: a parameter calculation means that sequentially obtains parameters based on temperature detection signals during fluctuation control;

According to the present invention, the forced fluctuation control of each energizing current is sequentially performed, and during the fluctuation control, the other heaters are simultaneously energized based on their temperature detection signals and control parameters. Each control parameter is determined in a state similar to an actual control operation in which adjacent heaters thermally interfere with each other, and therefore it is possible to accurately determine each control parameter that is optimal for heater control.

(Explanation of Examples) Hereinafter, preferred embodiments of the device according to the present invention will be described.

Heater 10-1.10-2.10-3.10- in Figure 1
4 are provided in the heating cylinder 12 of the injection molding device, and therefore thermal interference occurs between adjacent ones.

And those temperatures are measured by temperature sensors 14-1, 14-2.
14-3 and 14-4, respectively, and the temperature sensor 1
4-1.14-2.14-3.14-4 detection signal is A
The signal is input to the CPU 18 via the /D converter 16.

Furthermore, the input values of these temperature detection signals are R as shown in Figure 3.
The data are stored in the first, second, third, and fourth channel data storage areas provided in the AM 20, respectively.

These channel data storage areas are equipped with a heater 10-1.
．． Setting values indicating target temperatures of 10-2, 10-3, and 10-4 are also stored, and these setting values are given to the CPU 18 from the setting device 22.

In addition, control parameters P, I, and D are stored in each channel data storage area, and in CPtJ18, the control signal that matches the temperature input value to the set value is a PID calculation using the control parameters P, ■, and D. have been obtained.

The calculation is performed according to the contents of ROM24,
The energizing current according to the control signal of the CPtJ 18 is transmitted from the energizing circuit 26 to the heaters 10-1.10-2.10-3.10-.
4.

Here, a tuning command is given to the CPU 18 from the setting device 22, and when the CPU 18 receives this tuning command, a process for correcting the control parameters P, (2), and D is started.

For this process, the phase value and tuning flag value stored in each channel storage area as shown in FIG. 3 are used, and the subsequent heaters 10-1, 10-2, .
10-3. New modified control parameters are used for temperature control in 10-4.

FIG. 4 shows a flowchart of the processing procedure performed by the CPU 18, and when the power is turned on, the temperature input value from the temperature sensor 14-1.14-2.14-3.14-4 is taken in. (Step 200).

Then, when the set value of the setting device 22 is taken in (step 202), it is determined whether a tuning command has been given by the setting device 22 (step 204), and only when a tuning command has been given, a tuning flag is set. (Step 206).

Next, it is determined whether or not the tuning flag is set (step 208>, and if the tuning flag is not set (Stella '7208 No.
>, normal PID control is performed in which the energizing current supplied to the heaters 10-1.10-2.10-3.10-4 is simultaneously controlled (step 210).

In this embodiment, temperature sensor 14-1.14-2.14-3
．． The temperature detected by 14-4 is the heater 10-1.10-2.
．． 10-3. The currents are simultaneously PID-controlled in the direction matching the target temperature in 10-4, and in order to obtain these control signals, each control parameter P, ■, D in Fig. 3 is used.
is used.

Here, when it is confirmed that the tuning flag is set (step 208 YES), it is determined whether the phase value that has been reset in advance is O (step 212).
. Note that when the phase value is O, the heater 10-1.1
The energizing currents of 0-2.10-3.10-4 are simultaneously controlled as described above.

At that time, if the phase value is O (step 21.2
YES), the increment is performed (step 214>), and the same PID control as described above (step 210) is performed.
) is carried out.

Then, in the process of the next cycle, it is confirmed that the phase value is not O (step 212 No>), and it is confirmed that the needs value is 1 (step 216 YES).
, its value is incremented again (step 218
).

In the processing of the next cycle, it is confirmed that the phase value is not 1 (step 216 No>), and the need value is 2.
When it is confirmed that (Step 220 YE
S>, only the energization to the heater 10-1 of the first channel is stopped, and the energization is restarted after a predetermined time has elapsed (step 222).

When the current supplied to the heater 10-1 is forcibly controlled to fluctuate in this way, the temperature sensor 14 as shown in FIG.
The temperature detected by −1 decreases during phase 2 and returns to the target temperature again.

During this time, the control parameters P, ■, and D of the first channel are obtained from the rate of change of the detected temperature (step 224), and when the correction of the control parameters of the first channel is completed (step 226 YES), the phase 1
The channel is reset (step 228), and the pointer indicating the channel is incremented by one (step 230).

Next, it is determined from the value of the pointer whether the fourth channel control parameters P, I, and D have been modified (step 232>, the fourth channel control parameters P,
, D is not modified (step 232
No), the processes of steps 200 to 232 are repeated.

As a result, the control parameters of the second to fourth channels are successively verified.

When the control parameters of the fourth channel are modified (step 232: YES), the tuning flag is reset to 1 (step 234), and the value of the pointer is also roughly reset (step 236).

In this way, in this embodiment, forced current fluctuation control (
Step 222) is the heater 1o-1, 10-2, 10-
This is performed sequentially for the energizing currents of heaters 10-1, 10-2, 10-3, and 10-4.
The detected temperature changes sequentially as shown in FIG.

Then, the control parameters P, I, and D of the first channel, second channel, third channel, and fourth channel are sequentially determined from the rate of change of these detected temperatures (step 22
4).

When the parameters P, (2), and D of each channel are roughly corrected, the current flowing through other channels continues to be PID-controlled (step 210).

As explained above, according to this embodiment, each heater 10-
1.10-2.10-3.10-4 are sequentially controlled to fluctuate and only their control parameters are determined, while other currents are controlled by their temperature detection signals and control parameters P, ■, Since the energization is controlled simultaneously based on D, each control parameter P, ■, and D are successively corrected in a state similar to the actual control operation in which adjacent heaters thermally interfere, and therefore the heater 10-1.10 -2.10-3.
Each control parameter P, which is optimal for simultaneous control of 10-4,
It becomes possible to define D accurately.

As a result, it becomes possible to adjust the temperature of the heating cylinder 12 with high precision.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing a preferred embodiment of the device according to the present invention, FIG. 2 is a temperature characteristic diagram explaining the operation of the conventional device,
FIG. 3 is an explanatory diagram of the storage contents of the RAM 20 in FIG. 1;
FIG. 4 is a flowchart showing the procedure of processing performed by the CPU 18 in FIG. 1, FIG. 5 is a diagram explaining the operation phases of the embodiment in FIG. 1, and FIG. Characteristic chart shows the market. 10-1.10-2.10-3.10-4... Heater 12... Heating cylinder 14-1.14-2.14-3.14-4... Temperature sensor 18... CPU 20... RAM 22... Setting device 24... ROM 26... Energizing circuit

Claims (1)

[Claims] (1) An energization amount control means that simultaneously controls the energization current supplied to each of the plurality of heaters where thermal interference occurs based on the temperature detection signal and control parameter of each heater, and energization that forcibly controls the variation of each energization current. variable control current specifying means for sequentially specifying the energizing current to be fluctuatedly controlled; parameter calculating means for sequentially determining control parameters for each energizing current based on a temperature detection signal during fluctuation control of the energizing current; A heater control device comprising: